@Janx , I think your mention of Ripley illustrates why not all characters need to follow the same formula for character arc and such, and that adhering to such rules of writing is rather limited. It really depends upon the story.
Alien is much more of a set piece, a short story. Ripley is a cipher for the audience's experience of terror. Rey or Luke are portrayed over years, with a real arc of development.
That said, Ripley doesn't change and develop over the four movies she's in, and even in
Alien she goes from being second or third in command and part of a team, to having to deal with the creature on her own. But my point is, the necessity of a character arc isn't as great in her story as it is in the Star Wars films, and for Luke and Rey.